Paraffin scraper



Z'h/ lm March 17, 1953 F, CARSON 2,631,674

PARAFFIN SCRAPER Filed April 5, 1950 2 SHEETS--SHEET l /Z/ l illmuluumIl v mf JNVENTOR Ibrres Leon Carson ATToRA/Ey March 17, 1953 F CARSON 2,631,674

l PARAFFIN SCRAPER Filed April 5. 1950 2 SHEETS-SHEET 2 173915 @if W WENT 7 fbfrestlleon alfmz 76 75 7Z`F BY Z747 MKM H\ f4) /76 ATTORNEY Patented Mar. 17, 1953 PARAFFIN SCRAPER Forrest Leon Carson, Borger, Tex., assigner to J. M. Huber Corporation, Locust, N. J., a. corporation of New Jersey Application April 5, 1950, Serial No. 154,165

(Cl. 16S-18) 9 Claims.

string of smaller steel pipe inside the casing and generally knovvnas the tubing', a pump at the bottom of the well, and a string of steel rods, commonly referred to as sucker rods, Within the 'tubing and extending down into the pump for operating the pump. Means are provided atthe top Vof the Well for reciprocating the sucker rods to operate the pump. In many cases, the means for reciprocating the sucker rods include means yfor rotating the rods through a predetermined angle during each stroke of the sucker rods. Suitable apparatus of this character are shown -by Sargent in Patent 1,653,510, Poulsen in Patent 2,180,880 and T. De Witte McConahey et al. in Patent 2,444,842.

The crude oil generally contains parain and other substances which tend to congeal and precipitate yout of the oil' and deposit upon the walls of the tubing during the passage of the oil through the tubing. Such deposits are quite objectionable and tend to restrict the ilow of oil through the tubing.` Various means and methods have been proposed for preventing the formation of such deposits and for removing deposits so formed. Such means and methods comprise the use of chemicals, electrical heating, and various lmechanical scraping devices. In general, such means and methods are expensive and have other objectionable features.

A common mode, of preventing the formation of deposits on the tubing and removing suchde- -posits as they are formed, comprises attaching mechanical paraiiin scrapers to the sucker rods. Such Scrapers remove the deposits from the oil Well tubing as it is formed so that itr is -nshed' out of the Well With the oil passing @muy successful. lit isdiecult to fasten the blades to the sucker rod sufliciently firmly and there-is a tendency for the blades to become loose in operations extending over long periods of time. R. C. Lister, in Patent 2,468,503, has disclosed an improved method for attaching scraper blades of the type disclosed by Blackburn to the sucker rods. While such method of Lister results: in rmly Asecuring the blades toA the rods, it has the disadvantage that the sucker rods mustl be transported to a plant which is specially equipped for the attachment and replacement 'of the scraper blades.

It is an objectof my invention to provide a novel type of paranin scraper blade which is adapted to be detachably attached to sucker rods that :are simultaneously reciprocated and rotated. Another object is to provide a novel type of parafn scraper blade which can be securely attached to the sucker rods orremoved therefrom at the oil Well and without requiring transportation of the sucker 'rods to a separater plant for attachment or replacement of thescraper blades. A further object is to provide a sucker rod having parafn scraper blades detachably secured thereto in a Iirm manner and which can be quickly and easily removed from the sucker rod or replaced at the oil well. Furtherv objects are to advance the art'. Still further objects will appear hereinafter.

The abovey land other objects may 'bek accomplished in accordance with my invention which comprises providing an elongated paraffin scraper blade composed of steel atleast' 4 inches long and provided with an elongated opening having a width slightlyr greater than the diameter of the sucker rod iand a length of from about 3 to about 7.5 times its WidthV extending` coaxially of the blade, the end portions of the blade being about le to about 1/2' inch thick and extending beyond the ends of the'opening for at least 1/2 inch, and the side portions of the blade opposite the opening being composed of spring steel about le to about 1A inch thick.

Such paraffin scraper blade is adapted to be attached to the sucker rod by placing the blade so. that the end portions bear against one side of the sucker rod' and the opening is opposite the sucker rod', pressing the side portions of the blade midwayl their length to a position beyond the opposite side of the sucker rod, then inserting akeybetween such opposite side of the sucker rod and the side portions of the scraper blade, and then releasing the sides ofthe blade so that theyy spring jpartway backl to 'bear against the key with a spring tension ofkf'rom about 1 00 to about 50o pounds. suchI spring tension-is sumcient to maintain the scraper blade and key firmly in position by the friction of the surfaces of the end portions of the blade and the surface of the key on the surfaces of the sucker rod, and it is unnecessary to otherwise secure the key to the scraper blade. Such scraper blade can be easily removed for repair or replacement by reversing such operation.

It will be apparent that such scraper blades are simple and economical and may be quickly and easily applied to the sucker rods or detached therefrom at the oil well without transporting the sucker rods to a special plant and without shutting down the well for any considerable periods of time.

Each sucker rod will be provided with one or more of such scraper blades extending for substantially its length. Usually, each blade is from 4 inches to about 3 feet in length, and each sucker rod will carry a plurality of suchblades spaced longitudinally of the rod at distances less than the length of the stroke of the rod. However, a sucker rod may carry a single scraper blade having a length substantially equal to the length of the sucker rod.

Preferably, when a scraper blade is suiiciently long, it will be provided with a plurality of such elongated openings spaced longitudinally of the blade. Also, preferably, such a blade will be atvtached to the sucker rod at each opening in the manner heretofore described. A blade having a plurality of such openings will have an elongated opening and also may be considered to be a series of connected scraper blades each having an elongated opening.

I'he scraper blade, when attached to the sucker rod, should be under a spring tension of from about 100 to about 590 pounds, that is. should exert a total force of from about 100 to about 500 pounds on the surface of the sucker rod. Usually, a total force of about 100 pounds is sufficient for 'a scraper blade up to 1 foot in length. The maximum force will depend upon the size and strength ofthe sucker rod and should be insufficient to bend the rod. A force of 400 to 500 pounds, exerted over not more than 1 foot of the length of the sucker rod, is permissible for the usual sucker rod of /8 inch diameter. The selection of the spring steel for each scraper blade is within the skill of the art.

In order that my invention may be more readily understood, reference will be made to the .following detailed description and claims taken in connection with the accompanying drawings wherein like reference characters designate like parts.

Fig. 1 is a front View of one form of the paran scraper blades of my invention, showing it attached to a sucker rod;

Fig. 2 is a side View of the structure of Fig. 1;

Fig. 3 is an end view of the structure of Fig. 2, with the sucker rod shown in cross section;

Fig. 4 is a view similar to Fig. 1, showing a different form of scraper blade of my invention;

Fig. 5 is a side view of the structure of Fig. Zi;

Fig. 6 is an end view of the structure of Fig. 5, with the sucker rod shown in cross section;

Fig. '7 is a plan view of a blank for forming into a Ythird form of scraper blade of my invention;

Fig. 8 is an end view of the structure of Fig. 7; Fig. 9 is a view similar to Fig. '7, showing the scraper blade formed for attachment to the ,sucker rod and with the blade placed on the v.sucker rod ready for attachment thereto; v .A Fig. 10 is an end view of the structureof Fig. 9;

Fig. l1 is a side view of the structure of Fig. 9, with the blade secured to the sucker rod;

Fig. 12 is a plan view of the side parts of a fourth form of scraper blade of my invention;

Fig. 13 is an end view of one of the connecting end parts for connecting the side parts of Fig. 12; and

Fig. 14 is a side view of the structure of Fig. 13.

Referring more particularly to the structure of Figs. 1 to 3, a sucker rod 20 about 5/8 inch in diameter has attached thereto a scraper blade 22 about 6 inches long provided with an elongated opening 24 about 3A inch wide and about 41/2 inches long extending coaxially of the blade. In this instance, the ends of the opening are rounded, but they may be square if desired. The scraper blade 22 is made of spring steel about 1A; inch thick, and may be considered to consist of two spaced similar connecting end parts 2S and two spaced similar elongated side parts 2&5 provided with scraping edges 30. The scraper blade is about 2%; inches wide, although it will be understood that the width of the blade will vary with the size of the tubing in which it is to be employed so that its width will be slightly less than the diameter of the tubing and the scraping edges 30 will be adjacent the inner surface of the wall of the tubing, as is well known to those skilled in the art. The side parts 26 of the scraper blade have been pressed under spring tension to a position beyond the side of the sucker rod opposite that upon which the connecting end parts 28 rest, have had a key 32 inserted between the rod and the side parts 26 of the scraper blade, and the side parts of the scraper blade had been allowed to spring back so that they bear upon the key 32 with a spring tension of from about to about 500 pounds.

The key 32 is shown as a at steel strip about 1/8 inch thick, about 3A inch wide and about 2 inches long. It extends transversely across the opening 24 in the scraper blade and the side parts 2S of the blade at the bottom of the bends therein and has a wide surface at its midportion bearing against a side of the sucker rod and the opposite side surface of its ends bearing on the wide surfaces of the side parts of the scraper blade.

The scraper blade 22 may originally be a single flat strip of spring steel which is sufficiently flexible to be bent under spring tension as above described. Usually, however, the blade will be stamped out of sheet steel and formed with its connecting parts 28 bowed so that their inner surfaces are curved on a radius substantially equal to the radius of the sucker rod, providing large bearing surfaces to contact the sucker rod. Also, each side part 25 of the scraper blade is usually preformed in bent position so that its midporticn will be spaced from the plane connecting its ends by a distance less than the diameter of the sucker rod. The cumulative preformation of the connecting parts and side parts will be such that, when the blade is placed upon the sucker rod with its connecting partsv bearing against aside of the sucker rod, the midportion of each side part will be adjacent the opposite side of the sucker rod. After being so formed, the blade will be tempered or otherwise heat treated to give it the desired springiness. For example, a scraper blade o such construction was made from SAE 1075 carbon steel and, after preforming, heat treated at a Rockwell C scale of 51-52 to -give a Brinell hardness .of about 51e-534,. They key wasgmade of the same Ama- .an enlarged bearing surface.

teral. Such preforming of the scraper blade permits the'use of stiier spring steel.

It will be Yunderstood that the dimensions heretofore given are for illustrative purposes solely. The blade may be from about 11g to about 1/4 inch thick. The width of the opening, the distance between the opposed inner edges of the side part-s, will depend upon .the diameter ofthe sucker rod to which the blade is to be attached and will Vbe slightly greater than the diameter of the sucker rod so that the blade can be applied to the sucker rod inthe described manner. The opening may be from about `3 to about 7.5 times its width. The blades should be atleast 4 inches long and may be Ivas long vas desired. However, blades, of the type shown inFigs. l to 3, will preferably be fromabout 6 to about 12 inches long. The connecting end par-ts of the blade should extend for at least 1/2 inch beyond the ends of the opening, so as to provide sufficient strength to prevent them readily breaking in service.V Usually, the connecting end parts 28 Will befrom about 1%, to about 1 inch Wide. While I have shown the blade as being tapered toward its ends, it will be understood that this is not necessary but that it may be of the same wid-th vthroughout its length, Vwith square ends. How'- ever, in the latter case, it will usually be desirable to have the corners rounded so as to avoid sharp corners.

rigid steel than the blades, and may be :from

Vabout #s to about 1/2 inchA thick. The keys may be as long as the width of the blade but should not exceed the Width of the blade. Preferably,

'they are made slightly shorter than the width of the blade.

Figs. 4 to l6 illustrate another form of scraper blade 34 of my invention attached to the sucker rod 2li. This scraper blade is provided with two longitudinally spaced openings 3,5, similar to the opening 24 of the scraper blade of Figs. l'to 3. Otherwise, the scraper blade 34 is similar to that of Figs. 1 to 3 and may be made and secured to the sucker rod in the same manner. vItv is composed of two side parts 38, two connecting end parts 42., and a middle connecting part 4 5 between the two openings and similar to the connecting end parts 42 and functioning in a similar manner.y The side parts 38, midway the length of the openings, have been pressed under spring `pressure to a position beyond the opposite side of the sucker rod and the keys 43 inserted as shown-and as described in relation to`Figs.,1 to 3. In this case, the key 4S is bowed midway between its ends so that the radius of the .inner surface of the bowed portion 4 is substantially equal to the radius of the sucker rod, forming As in the case of the structure of Figs. 1 to 3, the blade 34 may be made of a flat spring steel strip which is suinciently elastic so that it can be sprung'into the desired position Without exceeding its elastic limit. However, in practice, the scraper blade 34 is made oi sti'er spring steel, such as SAE 1G75 carbon steel, and the connecting parts 42 and 46 preformed with bowed midportions rand the side parts 38 preformed in bent position inthe manner heretofore described with respect to the blades of Figs. 1 to 3. Preferably, the bowed portionsof vtheconnecting partsV will extend over an arc of from about 60 to about 180, generally about 60 to about 80. Usually the 'blades of Figs. 4 to 6 will be from 6 inches up to about 3 feet in length but preferably will be from about 8 to about l2 inches in length. Their dimensions may be otherwise varied as described with respect to the blades of Figs. 1 to 3.

It will be apparent that blades, of the character shown in Figs. 4 to 6, may be made as long `as desired up to the length of the sucker rod and provided with three or more longitudinally spaced openings similar to the two openings shown in Figs. 4 to 6.

Figs. '7 to 11, inclusive, illustrate a third form oi scraper blade of my invention. In this structure, the blade 52 is a substantially rectangular strip of steel provided lwith a rectangular opening 54 extending coaxially of the blade, and consists of connecting end parts 6U and elongated side parts 55 having outer scraping edges 58. It is originally in flat form as shown in Figs. '7 and 8 which, if the blade is to be applied to a 1/2 inch sucker rod, will be about 21A; inches in width with the opening about 1% inches wide. The end parts 6U will then be formed to be permanently bent about the axis of the blade into substantially U-shaped form as shown at 62 in Fig. 10 with the inner surface having a radius substantially equal to the radius of the sucker rod over an arc of abou-t The blade is then heat treated in known manner to give it the desired spring steel characteristics.

The bending of the connecting end parts 50 brings the side parts t closer together so that the opening Eli will be about inch measured from the inner edge of one side part 5S to the inner edge of the other side part 5E; or, in other words, the straight-line distance, between the junctions of each .connecting part with the respective inner edges of the side parts, will be slightly v greater than the diameter of the sucker rod. The

outer scraping edges 58 will then be spaced apart by the distance required by the tubing in which the blade is to be used. Such bending of the connecting end parts 6s also brings the side parts 56 to a position adjacent the side of the sucker rod opposite to that against which the midportions S2 of the end parts will bear.

This blade 52 as so formed will be placed upon the sucker rod as shown in Figs. 9 'and 10, then the midportions of the side parts 55 will be pressed beyond the sucker rod and a key 32, similar to that shown in Figs. l to 3, will be inserted in the manner hereinbeiore described with respect to the vother forms of blade of my invention. In this construction, since the entire blade is made of spring steel, the spring tension on the blade,

Awhen secured to the sucker rod, will tend to cause the lower portions of the legs of the U-shaped bends in the end parts to move toward each other and more rmly grip the sucker rod.

As described in connection with the other form of my invention the blade may be from about il; to about 1/4 inch thick, and the end parts 60 may extend for any desired distance in excess of 1/2 inch beyond the ends of the openings 54. Also, the form of blade shown in Figs. 'I to 1l may be made of any desired length up to the length of the sucker rod and provided with a plurality of longitudinally spaced openings 54, as has been heretofore described with respect to the other blades of my invention.

Figs. 12 to 14 illustrate a form of blade similar to that shown in Figs. 7 to 1l, but made of a plurality of separate pieces. As shown in Fig. l2,

"the side parts `Mare made' or two .similar :pieces v'of spring steel from about 11g to about' 1A inch thick, provided with outer scraping edges 66 and inner opposing edges 68. Each side part B4 is provided with a small opening at each end to accommodate a rivet. The connecting parts "i2 may be made of the same material as the side parts 64 or may be made of more rigid steel. These connecting parts 12 may be from about le to about 1/2 in-ch thick and should be at least x/2 inch wide. Each connecting part is formed with a U-shaped midportion, having the inner surface curved on lan arc of about 180 and having a radius substantially equal to the radius of the sucker rod to which the blades are to be attached. Each connecting part 12 is provided at ea-ch end with an outwardly extending foot M which extends outward for a distance substantially equal to the width of the side parts 64. Each foot 'M is provided at its center with an upstanding rivet 16 adapted to t in the openings 'i0 of the side parts 64.

The blade, to be attached to the sucker rod, is formed from the parts shown in Figs. 12 to 14 by placing an end part at each end of the pair of side parts, inserting the rivets 'I6 through the openings 1D, and riveting the parts together. Ihe scraper blade will then be applied to the sucker rod in the manner heretofore described with respect to Figs. '7 to ll.

It will be apparent that the structure of Figs. 12 to 14 can be considerably modiiied. The side parts 64 may carry the rivets 16 and the outwardly extending feet 14 of the end parts may be provided with the holes Ill. It is not necessary to make the rivets 'i6 integral with any of -the parts, but both the side parts and the end parts may be provided with registering holes for receiving rivets, bolts, and the like. Furthermore, holes and rivets may be eliminated entirely, and the side parts welded to the end parts. Still further, the side parts can be made considerably longer, upto substantially the length of the sucker rod, and secured to additional connecting parts 12 intermediate their lengths as well as their ends, so as to provide a scraper blade having a plurality of longitudinally spaced openings, similar to those described with respect to the other forms of my invention.

It will be understood that the forms of scraper blades shown in the drawings and hereinbefore described in detail are merely illustrative and that my invention is not intended to be limited to any of the specific embodiments so disclosed and described. Usually, the end parts or connecting parts will be from about 1/2 to about l inch Wide; that is, they will extend for that distance along the length of the rod. When the scraper blades are provided with a single opening, they will usually be from about 4 inches to about 12 inches long and a plurality of such blades will be secured to each sucker rod and spaced apart by distances slightly less than the length of 'the stroke of the rod in operation. When a scraper blade contains only two elongated openings it may be from about 6 inches to about 3 feet in length and each sucker rod will be provided with a plurality thereof spaced apart by a distance less than the stroke of the rod. The same considerations will prevail with scraper blades of greater length, but of insuihcient length to extend over more than onehalf the length of the sucker rod. It will also be understood that scraper blades of different forms and different lengths may be applied to a single sucker rod.

The resistance of the scraper blades to slipping on the sucker rod may be increased by providing hardened and rough or le-like surfaces on the connecting parts of the blades and on the keys. Also, if the end of the opening in the scraper blade is square across the longitudinal axis of the blade as in the forms shown in Figs. '7 to 14, they may be provided with sharp edges, whereby the spring tension will cause such edges to tend to bite into the rod and prevent slipping. Such expedients will reduce the spring tension required to maintain the scraper blades and keys in position. However, such rough bearing surfaces and sharp edges will generally be objectionable and usually will be unnecessary. Ordinarily, the surfaces of the scraper blades and of the keys will be substantially smooth, since the friction of the bearing surfaces on the sucker rod under the high tensions employed will be sufcient to maintain the scraper blades and keys in position on the sucker rod over long periods of service.l Obviously, high polished ,bearing` surfaces will usually be avoided.

It will be apparent that when the scraper blades are made with their connecting parts prebowed, or their side parts prebent, or both, the degree of prebowing and prebending may be varied from substantially zero to the maximum shown and described. That is, the distance, between the bends in the side parts and the midportions of the connecting parts measured perpendicular to the axis of -the blade,'may vary from zero up to substantially the diameter of the sucker rod to which the blade is to be attached.

While I have shown the keys as being bent at their mid-portion 50 in Figs. 4 to 6, it will generally be preferred to employ flat keys, such as those shown in Figs. 1 to 3. The at key will be maintained in position under ordinary conditions. Bowed keys, of the character shown in Figs. 4 to 6, make it necessary to spring the side parts of the blades greater distances beyond the adjacent side of the sucker rod to permit insertion of the keys. This increases the danger of bending the side parts beyond the elastic limit of the steel; or requires the use of more flexible steel, which must spring back a greater distance before the side parts contact the keys, so that part of the spring pressure will be lost and the maximum spring tension will not be obtained.

It will also be apparentthat the side parts need not be of the same width, but that one side part may be of a width to provide a paraffin scraping edge and the other side part be made considerably narrower so that its outer edge is spaced a materialv distance from the oil well tubing. However, such latter form of scraping blade does not have anysubstantial advantages over the double-edged scraping blades.

It will be seen that, by my invention, I have providedva novel type of paraiiin scraper blade which as adapted to be detachably attached firmly to a sucker rod and which may be readily and easily attached to the sucker rod or removed therefrom at the oil well, without requiring transportation of the sucker rod to a specially equipped plant or long shut downs of the oil well. It will also be seen that I have provided a novel combination of a sucker rod having firmly secured thereto in a novel manner a novel typeY of paraffin scraper, which scraper blade can be readily removed for repairs or replacement at the oil well. Furthermore, such paraiiin scraper blades, and the means for attaching them to the sucker rod, are simple and economical in construction and manufacture. Therefore, it will be apparent that analista portions. and spacedv similar connecting portions.

entending transversely between theside portions, the .side Yportions having outer scraping edgesand parallel-inner edges spaced apartby a. distance` slightly1 greater than the diameterv ofthe suckerV rod;v and the connecting.portionsbeing at least. 1/2 i nchv\ 1ided and spaced apart by a.l distance equal to from?, to about7-r5f times the diameter Oftne seeker roei andeaeh hei/ing allongitudinallybowed midportion whoseinner. radius is;

substantially equal to the. radius of the sucker 1:0115v the plane of the midportions of the conf neeting portionsl being spaced oppositely from. theplaneor the midportions of the side portions by al distanceup to substantially the diameter oi the sucker rod.

2, An elongated parain scraper blade adapted:`

t9 beattachedgto a sucker rod, which blade consistSQi a single slotted Stripof springsteel about 14e-,to about, Viinch thickl andat least 4 inches long 'and comprises spacedsimilar. elongated side portions and spaced similar*y connecting portions extending; transversely beiweenthe Sidepeiiiene,

thel side portions having outer scraping edges and` parallel. inner ensesSpeeedV apart by e disv tance slightly greater than the diameterv of the sucker resi endeteeen Side eertien beine beni transversely intermediate its ends; and the connecting portions. beingat least Mg inch wide and spaced apart by a distance equal to from 3 to aboutI '7.5 times the diameter of the sucker rod, and each having a longitudinally bowed mid.- portion whoseinner radius is substantially equal to the radius ofthe sucker rod; the plane of the midportions of the connecting portions being spaced oppositelyv fromthe plane of the midpoitions zofi the sideportiorlsby. ay distance upto Asubstantially` the diameter of thesucker rod;

3. An elongated. paraiiin Semper blndeiadnpied tope .attached to. sucker rod, which blade eensists of. a. single slottedstripot Spring Steel` alieni 1-6 to about 1A; inch thick and at least 4 inches long and consists of two spaced similar elongated side portions and two spaced similar connecting portions extending transversely between the side portions, the side portions having outer scraping edges and parallel inner edges spaced apart by a distance slightly greater than the diameter of the sucker rod; and the connecting portions being at least 1/2 inch wide and spaced apart by a distance equal to from 3 to about 7.5 times the diameter of the sucker rod and each having a longitudinally bowed midportion Whose inner radius is substantially equal to the radius of the sucker rod; the plane of the midportions of the connecting portions being spaced oppositely from the plane of the midportions of the side portions by a distance up to substantially the diameter of the sucker rod.

4. An elongated paraffin scraper blade adapted to be attached to a sucker rod, which blade consists of a single slotted strip of spring steel about le to about 1/4 inch thick and at least 4 inches long and consists of two spaced similar elongated side portions and two spaced similar connecting portions extending transversely between the side portions, the side portions having outer sc ing edges and parallel inner edges spaced ap I :by a 'distance 'slightly greater than" the' diarnetery of the ysucker rod and eachl side portion'v being bent transversely intermediate itsends; and the connecting portions bei'ngj'at least 1/2 inc hwijde and spaced apartby adistance equal' to troni 3; to about 7.5 times the diameterv ofthe suclger rod, andl each having a longitudinally bowed-midportion whose inner radius is substantiallyequalto the radius ofl the sucker/rod; the plane, o iV the midportions of the connecting por-l' tiolnsbeing spaced'roppositely from the plane "ofg themidportions ofthe side por-tions by 'a dis? tance up to substantially the diameter of the sucker rod;

5., An elongatedparaiiin scraper`v blade adapted togbe attached to a sucker rod,"WhichfbladeA 'consists of asingle slotted stripoffsprin'gfsteel aboutr to. about 1/4 inchv thick and atleast Gfincfhes long andrcomprises two vspaced similar elongated? side portionsl and three lspaced similar connecting? portions extending transverselyfbetween theside p'ortinnsY the side portions having outer scraping edges and parallelA inner edges spaced apart by 'a distance slightly greater than the diameter 'of`4 the sucker rod; and the connecting portions'beingatleast 1/'2 inch wide andspacedapart by a' dis; tanceeqnal to from` 3 to about 7.5 times the diam"- eter of the sucker Vrod' and each having a longitudinally bowed midportion whose inner radius is substantially equalfto the radius of the sucker rod; rthe plane ofthe midportions of the connecting portions being spaced oppositely from` the plane 'of the Vmidportions of the side portions by a distance up to substantially the diameterotthejsncker rod. E

6j. An elongated paraffinscraper blade adapted tobe attached'teoA a sucker rod, which blade consistsofa single slotted strip of spring. steel about g to about 1/4 inch thick` and at least 6 inches longand consists of 'two spaced'similar elongated side por-tions and three longitudinally spaced similar connecting portions extendingv transversely between the side portions, the sideV por-- tions having outer scraping edges and parallel inner edges spaced apart by a distance slightly greater than the diameter of the sucker rod and each side portion being bent transversely midway of each opening; and the` connecting portions being at least- 1/2' inch wide and spaced apart by a distance equal to from 3 to about '7.5 times the diameter of the sucker rod, and each having a longitudinally b-oWed midportion Whose inner radius is substantially equal to the radius of the sucker rod; the plane of the midportions of the connecting portions being spaced oppositely from the plane of the midportions of the side portions by a distance up to substantially the diameter of the sucker rod.

7. In combination, a sucker rod and an elongated parain scraper blade secured thereto, said blade consisting of a single slotted strip of spring steel about i1-6 to about 1/4 inch thick and at least 4 inches long and provided with 1 to 2 elongated openings each having a width slightly greater than the diameter of the sucker rod and a length of from about 3 to about '7.5 times its width extending coaxially of the blade; each of the transverse portions of the blade being at least V2 inch wide and bearing against the same side of the sucker rod, and being permanently bowed about the longitudinal axis of the blade so that the surfaces bearing upon the sucker rod are curved on a radius substantially equal to the radius of the sucker rod; the side portions of the blade op- 11 y o posite the opening having outer scraping edges and, being bent transversely midway their length under a spring tension of from about 100 to about 500 pounds to a position adjacent the opposite side of the sucker rod; and a steel key from about 11g to about 1/2 inch thick and from about 1/2 to about 1 inch wide extending transversely across the opening and the side portions of the blade atthe bottom of the bends therein, a wide surface of the midportion of the key bearing against the aforesaid opposite side of the sucker rod and the opposite surface of the ends of the key bearing upon the surfaces of the side portions of the blade and holding the side portions in their spring bent positions.

8. In combination, a sucker rod and an elongated paraflin scraper blade secured thereto, said blade consisting of a single slotted strip of spring steel about le to about 1A inch thick and at least 4 inches long and provided with a single elongated opening having a width slightly greater than the diameter of the sucker rod and a length of from about 3 to about 7.5 times its width extending coaxially of the blade; the end portions of the blade extending beyond the ends of the opening for at least 1/2 inch and bearing against the same side of the sucker rod and being permanently bowed about the longitudinal axis ofthe blade so that the surfaces bearing upon the sucker rod are curved on a radius substantially equal to the radius of the sucker rod, the side portions of the blade opposite the opening having parallel inner edges and outer scraping edges and being bent transversely midway their length partially permanently and partially under a spring tension of from about 100 to about 500 pounds to a position adjacent the opposite side of the sucker rod; and a steel key from about 11g to about 1/2 inch thick and from about l to about 1 inch wide extending transversely across the opening and the side portions of the blade at the bottom of the bends therein, a wide surface of the midportion of the key bearing against the aforesaid opposite side of the sucker rod and the opposite surface of the fends of the 4 key bearing upon the surfaces of the side portions of the blade and holding the side portions in their spring bent positions.

9. In combination, a sucker rod and an elongatedA paraiiin scraper blade secured, thereto, said blade consisting of a single slotted strip of spring'- steel about 11,; to about 1A inchthick and at least 6 inches long and provided with two longin tudinally spaced elongated openings each having a width slightly greater than the diameter of theV sucker rod and a length of from about 3 to about, 7.5 times its width extending coaxially of theblade, the transverse portions of the blade between the openings and beyond the ends of the openings being at least 1/2 inch wide and bear-l ing against the same side of the sucker rod and being permanently bowed about the longitudinall axis of the blade so that the surfaces bearing"- upon the sucker rod are curved on a radius substantially equal to the radius of the sucker rod," the side portions of the blade opposite the open` ings having outer scraping edges and parallel inner edges and each side portion being benttransversely midway of each opening partially permanently and partially under a spring tension' of from about to about 500 pounds to a position adjacent the'opposite side of the sucker rod;

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 372,625 Jones Nov. 1, 1887 662,847 Wood Nov. 27, 1900 758,780 Renaker May 3, 1904 1,566,451 Vaughn Dec. 22, 1925 2,321,275 Blackburn June 8, 1943 2,575,307

Walker Nov. 13, 1951 

